After a scrappy opening half-hour, Taggart broke the deadlock with a superb volley from the edge of the area.
The impressive youngster doubled the Jets' lead with a superbly-taken goal in the 55th minute and, after the Heart got one back through Andrea Migliorini's deflected free-kick, completed his treble with 28 minutes remaining.
Taggart limped off with an injury late on but received a rousing reception from an appreciative home crowd after setting up a third straight win for his side.
Melbourne were the better side for much of the first half yet paid the price for failing to translate their dominance into a goal seven minutes before the break.
Taggart struggled to control a pass from Ruben Zadkovich but improvised to smash a volley past Andrew Redmayne, sending the crowd into raptures.
A melee broke out moments later when Heart players reacted to a late challenge from Taggart, who picked up a yellow card along with Zadkovich.
The latter missed an excellent chance to double his side’s lead on the stroke of half-time, but it mattered little as Taggart scored again in the 55th minute, curling a shot into the bottom-right corner following a pass from Jacob Pepper.
Migliorini reduced his side's arrears with a set-piece that took a huge deflection off Jets defender Josh Mitchell.
Yet Taggart had the final say, completing his first A-League hat-trick with a cool finish after finding acres of space on the edge of the area.
